TreatmentUpdate57, Vol. 7, No. 3 - March 1995
Sean Hosein

Learning that CMI (cell-mediated-immunity) was reduced in patients with AIDS a research team led by Dr. J. Salk (creator of the polio vaccine) designed a potential anti-HIV vaccine called the immunogen. To make this vaccine, technicians attacked HIV with chemicals and radiation so that it could not cause any infection. They then removed the HIV-protein gp120. This protein can impair the ability of the immune system to fight HIV. To boost the response of the immune system to the vaccine, researchers used an adjuvant called IFA (incomplete Freunds adjuvant) using light mineral oil and other ingredients. IFA appears to stimulate both CMI and humoral immunity. The researchers also used a small amount of another HIV protein called p24 with the adjuvant.

* STUDY DETAILS

All subjects in this study were adults, had CD4+ cell counts of at least 600 cells, and had no symptoms of HIV infection. As well, subjects did not have B-cells producing high levels of unnecessary antibodies. Researchers randomly assigned subjects to receive 3 injections of the vaccine or just the adjuvant over six months.

* MEASURING T CELLS

Different labs have different procedures for reporting a person's CD4+ cell count. Sometimes the actual number of CD4+ cells is computed. Sometimes it is not. CD4+ cells are lymphocytes, and lymphocytes are white blood cells. The white blood cells are expressed as an estimate of the actual number of white blood cells in 1 cc of blood. CD4+ cells are usually expressed as percentages. For example, usually lymphocytes make up between 25% and 50% of all white blood cells. Normally, CD4+ cells make up 30% to 45% of all lymphocytes. This is an actual measurement. To find out the CD4+ cell count some small calculations are needed. Thus CD4+ cell counts are calculated while the %CD4+ are actual measurements. Thus %CD4+ and %CD8+ are more accurate than the calculated number of cells. In a future issue of TreatmentUpdate we will provide details on how to find out the number of CD4+ and CD8+ cells

* RESULTS--CD4+ CELLS

At the time subjects entered the study their average %CD4+ (the proportion of lymphocytes that were CD4+ cells) was roughly 31%. Subjects who received the immunogen had a slower rate of loss of CD4+ cells compared to subjects who received IFA. This difference between the two groups was statistically significant that is, not likely due to chance alone.

* RESULTS--ANTIBODIES

Both groups of subjects produced increased amounts of antibodies against the HIV protein p24. Subjects who received the immunogen made more antibodies. This difference was also statistically significant.

* RESULTS--CMI, VIRUS AND TOXICITY

To measure CMI technicians inject a small amount of protein from yeast or bacteria under the skin. In people with good CMI there is usually a reaction within 48 hours-swelling and redness at the injection site. The greater the reaction the higher the level of CMI. Among the subjects given the immunogen, CMI apparently increased by 21% while subjects in the IFA group had their CMI fall by 28%.

It appeared that subjects who received the vaccine had a slower increase in production of HIV compared to who subjects received IFA. Again this difference was also statistically significant. Although some subjects used AZT while in the study, it did not appear to reduce production of H[V during the study. Researchers reported no serious side effects in people in both groups.

REFERENCES:

1. Trauger RJ, Ferre F, Daigle AE, et al. Effect of immunization with inactivated gp120-depleted Human Immunodeficiency Virus type 1 (HIV-1) immunogen on HIV-1 immunity, viral DNA and percent of CD4+ cells. Journal of Infectious Diseases 1994;169:1256-1264.

2. Moss RB, Ferre F, Trauger R, et al. Inactivated HIV-1 immunogen: impact on markers of disease progression. Journal of Acquired Immunodeficiency Syndromes 1994;7 (Supplement l):s21-s27.

3. Smith GW. Calculating your absolute T4+ count. IN: Testing AIDS 1989; page 4.

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Copyright © 1995 - TreatmentUpdate. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Canadian AIDS Treatment Information Exchange, 555 Richmond St. West, Suite 505, Box 1104, Toronto, ON, M5V 3B1 • Phone: 416-203-7122 • Toll Free: 1-800-263-1638 • Fax: 416-203-8284  http://www.catie.ca